With the Supreme Court’s decisions this week throwing out a key provision of the federal Defense of Marriage Act, and letting stand a state court’s rejection of California’s voter-approved same-sex marriage ban -- the battle now moves in large part to the states.

Including California, 13 states (in addition to the District of Columbia) will allow these marriages. The rest won’t, meaning married same-sex couples living there -- even if they legally marry somewhere else -- won’t have access to federal marriage benefits. Unless, that is, legislators or voters change the laws. Senator Diane Feinstein of California quickly introduced legislation after the Supreme Court’s decisions to extend federal marriage benefits to married gay couples living in all states. But it’s not expected to get anywhere in the House, even if it makes it through the Senate.

The liberal and conservative groups on either side of the marriage debate are already gearing up for their state-by-state battle. Voter initiatives could be on the ballot in Oregon, Nevada and Ohio as early as 2014 to allow same-sex marriage, and legislative processes are moving forward in other states, such as Illinois and New Jersey.

Opponents of same-sex marriage have just lost at the Supreme Court; in the six states that approved same-sex marriage in the past year; and, they’ve been losing the fundraising battle.

“Our greatest strength is mobilizing people, particularly in the Christian community through churches and so forth,” says Peter Sprigg at the Family Research Council. “But raising money is a greater challenge for the pro-family movement.”

Sprigg says regular churchgoers tend to give to their church first -- in the form of a tithe -- before giving to conservative political campaigns. And he says wealthy business owners might hesitate to give based on their conscience, for fear of being targeted for boycott or retaliation by same-sex-marriage activists.

“They believe passionately in the righteousness of their cause,” Johnson says. “They often feel like they’re making a difference if they’re threatened. So I wouldn’t be surprised to see the anti-same-sex-marriage side doing quite well in fundraising in the coming days and months.”

As for the side favoring marriage equality, the Supreme Court just galvanized its supporters to get the job done all over the country, says Danielle Moodie-Mills at the Center for American Progress.

“You’re talking about going door-to-door, meeting with legislators, rolling out radio ads and television ads and flyers. And that takes a ton of money.”

For instance, Bill Lunch, former chairman of the political science department at Oregon State University, predicts each side in Oregon’s upcoming ballot fight will want to raise at least $1 million to compete and put their case credibly in front of voters; $2 million would be more comfortable. Lunch thinks the pro-same-sex-marriage side will raise more, but both sides will field a serious effort.

And he says their money will go to different things. Conservatives will try to mobilize primarily voters who are white, Republican, older (over 50), and regular churchgoers. He says it’s most effective to reach them using sophisticated database-sorting that aligns voters’ demographic blocs with specific radio and television shows and other consumption patterns. Direct mail is also effective with this demographic.

For proponents of same-sex marriage, the target audience is female, minority, young and primarily Democratic. For them, social media is a key mobilization tool.

But, with so many hot-button social issues in front of voters -- marriage, abortion, inequality -- could advocates on the same side of these issues end up competing for money, leading to political donor fatigue? Bert Johnson doesn’t think that's much of a danger -- at least not in the immediate aftermath of the Supreme Court's decisions.

“People tend to donate based on one particular issue or a small set of issues,” says Johnson. “I think it’s not a zero-sum game, it’s more likely to be a positive-sum game.”

Johnsons says right now, on this issue, motivated donors are likely to keep taking out their checkbooks again and again.